somewhat OT inkjet unclogging.

Ahem... this is not so quite on topic but I'm sure there is several classic 10 years old inkjet printers but my line of work involves pirnters that doesn't have removeable inkjet printhead ie: epson inkjets. Their replacement inkjet printhead cost over 100 and value on those printers when new is appox 170 to 250 when new. Even HP have gone in that direction for high end printers recently. Now, on unclogging inkjet nozzles. Ususally works but one day I had enough and thought of investing into big gun to do the job. The "big gun" is ultrasonic cleaner pot. Did anyone experienced that this works on badly clogged inkjet printheads? If so, what working cleaning fluid? Pure alcohol? Distilled water? In past, tried pressure unclog method using hobby silicone fuel tubing and 10cc injecter without needle filled with methyl hydrate alcohol 99.9 pure, I find it mose of a crapshoot than high rate success rate. Ink fluid is usually either coloured clear solution or finely powdered in fluid carrier (black usually). Cheers, Wizard